Over time, little bits and pieces of grass die and gather just above the soil. This is called thatch. A little bit of thatch can be beneficial. It’s organic material that is broken down by microbes in the soil. But sometimes, thatch builds up too fast for natural processes to break it down. It forms a barrier, keeping moisture and air from going where your grass needs it. A half-inch or more of thatch can weaken your lawn. You have 2 ways to remove it: dethatching and aerating.
For cool-season grasses, the best time to dethatch is late summer or early fall. That’s when your grass is growing most vigorously. For warm-season grasses, dethatch in late spring or after the second mowing. Before dethatching, mow a little shorter than normal. For more information visit Scotts